The demand for SDN is being driven by major communications service providers and major enterprises, versus the network equipment manufacturers (NEMs). If you were a telecom service provider or other major consumer of network infrastructure equipment, SDN is in theory very attractive for various reasons, such as the ability to only wire your network once and only once and use centrally controlled, lower-cost switches from multiple vendors

SDN is still in "early adopter" stage but moving fast. Companies like Google and Amazon have proven out the concept. However, market requirements to support service providers and major enterprises are still evolving. What are the various use cases that need to be supported? What type of programmatic interfaces should be presented? What types of network applications need to be supported?

From our past we learned split architecture from PSTN to VoIP with MGW connecting to CS services (MSC Server) and IMS Services (MCRF) using BICC, H.248 on IP, but now it will be SDN convergence with Data plane and Network operating system on control plane.

Marilyn, thanks for the greetings - yes now I feel much more comfortable with SDN. From what I understood, the essence of SDN is the separation of control plane and data plane. This is not some new concept and modern switches/routers adopted it widely. But SDN put the physical network infrastructure as a pure resource pool and data plane. Instead by making the control plane ("controller" in SDN terminology) separate and providing necessary intelligence/programming API, SDN offers not only higher efficiency on resource utilization, but also provides possibility for redefining the virtual overlay network. So far I did not see so many great examples in the market but I do believe it will contribute more and more to IT area, especially cloud computing and big data.

Virsingh, I think awareness is probably just beginning, as you say. Companies that define themselves and really rely on their network as a basis for their business are much more ahead of the learning curve, I would say.

@Susan, i guess my comment went in different direction, you might interviewed or met number executives around you, how many of them do you think are aware and had knowledge on SDN...i am not sure about there in US but people i meet still only SDN= Software Defined Networking...

Sam, I share your sympathy. I read about how companies are embracing SDN because current products didn't allow them to do what they needed with their networks, and I understand that. But for every company (like Google) that has a team of network engineers working out the complexities of virtual resource allocation, there are probably a thousand with limited networking and data center expertise who are very worried about how this will affect them.

When it comes to SDN, I feel for IT managers. While Google perhaps is the most well know example of a company that implemented SDN in the data center and in the network interconnecting their data centers, what I understand is that Google deployed a modified version of the OpenFlow protocol (GoogleFlow?). And they did deploy SDN pretty quickly. But how many IT managers have the resources that Google has?

I really was not being critical about the numbers, but trying to make the point that various market estimates related to SDN should probably only be viewed as providing a sense of how this market might grow going forward since we have no historical data upon which to forecast the market with any accuracy.

Something else that comes to mind is that much of the SDN activity currently is targeted at the at the data center. Service providers, as far as I know, are taking a much more cautious approach, although I'm pretty sure they too will embrace SDN. Yet another market for SDN is the campus network--again I'm not hearing much at this time about SDN in the campus.

Li, thanks for your comment. I am glad you found this an adequate overview. I thought readers might appreciate a basic explanation of the technology without all the complexity of how each vendor is approaching SDN. Are you experimenting with SDN yet?

Our latest survey shows growing demand, fixed budgets, and good reason why resellers and vendors must fight to remain relevant. One thing's for sure: The data center is poised for a wild ride, and no one wants to be left behind.